PELYUKH, G. P.; SAMOILENKO, A. M. Solutions of systems of nonlinear functional-differential equations bounded in the entire real axis and their properties. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 6, p. 737–747, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5701. Acesso em: 5 dec. 2025.